PURPOSE: To obtain an inexpensive sealing member, consisting of a reinforcing fiber aggregate having ceramic layers on the surfaces of metallic fibers, powdery boron nitride and binder and having improved pressure, heat and abrasion resistance and useful for high-temperature fluids.

CONSTITUTION: A sealing member consisting of (A) a reinforcing fiber aggregate prepared by forming ceramic layers on the surfaces of metallic fibers, e.g. titanium (alloy), etc., by a gas nitriding treatment method, etc., (B) powdery boron nitride having a hexagonal crystal structure filled in the interstices of the component (A) and (C) a binder for bonding the components (A) and (B). The ceramic layers of the component (A) preferably contains at least any one of titanium nitride, titanium carbide and titanium diboride.

USE: Autoclaves, casting machines, high-speed transferring means for molten metal, etc.